An unlikely combination of a not-so-useful anaesthetic and the stuff that makes chilli peppers hot, could ease future visits to the dentist. Alexander Binshtock, Bruce Bean and Clifford Wolf from Massachusetts General Hospital and Harvard Medical School have combined a painkiller with capsaicin, the vital ingredient in chilli peppers, to create a targeted anaesthetic.

QX-314 is a sodium-channel blocking painkiller that has not found medical use because of its inability to penetrate fatty layers around nerve cells. However, the team found that, with the help of capsaicin, it can make it through. More important, the capsaicin only lets QX-314 into the nerve cells that are particularly responsible for the sensation of pain – a selectivity that is completely novel. In short, pain relief is achieved without any numbness or associated paralysis.